Experimental studies on bone marrow stromal cells (BMSCs) transplantation into the ischemic myocardium

Objective To study the hypothesis that bone marrow stromal cells (BMSCs), when implanted into myocardium, can undergo proliferation and differentiation and improve the heart function.Methods Adult Lewis rats, a kind of isogenic rats, were used as tested animals. BMSCs labeled with BrdU were transplanted into the infarcted myocardium whose corresponding coronary arteries have been ligated. BMSCs's proliferation and differentiation and their angiogenic function 4 weeks later were observed. Ultrasound was also used to detect their effects on heart function.Results Four weeks after transplantation, the BrdU labeled BMSCs could be found in host myocardium. The majority of them had been differentiated into cardiomyocytes with the expression of myosin heavy chain. In addition, the positive staining of ⅢⅤ factor indicated there were a great deal of neovascularation in host area (23±4/HPF), while a little in control group (2±1/HPF) (P0.01). Echocardiography indicated that the heart function had a great improvement after BMSCs transplantation. Ejective fraction (EF) was increased from 0.458±0.063 to 0.709±0.137 in transplantation group, while it was decreased from 0.428± 0.176 to 0.334±0.161 in control group (P0.01).Conclusion BMSCs can be differentiated into viable cardiomyocytes when transplanted into infarcted myocardium and can improve the heart function remarkably.